Error "Undefined array key "id""

[BenS89]

Steps to reproduce

1. Install Nextcloud Mail app in the newest version (Nextcloud 33 and Mail App v. 5.7.1)
2. Setup a 2FA App Password for an iCloud Mail account
3. Login with this App password in Nextcloud Mail

Expected behavior

All mails are fetched from the iCloud Mail Servers and displayed within the Nextcloud Mail app

Actual behavior

No emails are shown. Instead, you can see the following error hundreds of times within the logs:

Undefined array key "id" at /var/www/html/nextcloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php#1007

Mail app version

5.7.1

Nextcloud version

33.0.0

Mailserver or service

Apple iCloud

Operating system

Ubuntu 24.0.4 LTS

PHP engine version

PHP 8.3

Nextcloud memory caching

No response

Web server

Apache (supported)

Database

MariaDB

Additional info

No response

[kesselb]

Thanks for your report.

I'm unable to reproduce with my icloud account.

Socket.php#1007

https://github.com/bytestream/Imap_Client/blob/33dc825bb4fb0a3fc6c892625404807aee7cd861/lib/Horde/Imap/Client/Socket.php#L1007 is related to the imap client id.

Sending the client id was enabled with #12259 recently.

The response from icloud for me looks like:

S: 3 OK ENABLE completed
S: * ID ("name" "iCloud Mail" "version" "2606B152")

Could you enable the account loggin (https://docs.nextcloud.com/server/latest/admin_manual/groupware/troubleshooting.html#logging-the-imap-smtp-sieve-connections) and see if the id from icloud is the same/similar?

If you comment the following lines in your instance, does the errors stop and makes your mailbox accessible again?

mail/lib/IMAP/HordeImapClient.php

Lines 45 to 53 in d4b222a

	if ($this->capability->query('ID')) {
	try {
	$this->sendID();
	/* ID is queued - force sending the queued command. */
	$this->_sendCmd($this->_pipeline());
	} catch (Horde_Imap_Client_Exception_NoSupportExtension) {
	// Ignore if server doesn't support ID extension.
	}
	}

[BenS89]

Thanks for your reply.

I started a debugging session and the iCloud answer looks the same:

S: 3 OK ENABLE completed
>> Command 3 took 0.1498 seconds.
S: * ID ("name" "iCloud Mail" "version" "2606B152")
S: 4 OK ID completed (took 0 ms)
>> Command 4 took 0.3225 seconds.
C: 5 ID NIL
S: * ID ("name" "iCloud Mail" "version" "2606B152")
S: 4 OK ID completed (took 0 ms)

Commenting the above section fixes the error message within the logs, some mails get fetched now and are therefore visible within the Mail app but another error occurs preventing from fetching all mails:

{"reqId":"ivD16zwRYo4xTLWT5nBo","level":3,"time":"2026-03-04T17:50:09+00:00","remoteAddr":"","user":"--","app":"mail","method":"","url":"--","scriptName":"/var/www/html/owncloud/cron.php","message":"Cron mail sync failed for account 20","userAgent":"--","version":"33.0.0.16","occ_command":["/var/www/html/owncloud/cron.php"],"exception":{"Exception":"OCA\\Mail\\Exception\\ServiceException","Message":"Could not get message flag options from IMAP: IMAP error reported by server.","Code":0,"Trace":[{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":492,"function":"isPermflagsEnabled","class":"OCA\\Mail\\Service\\MailManager","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":269,"function":"runPartialSync","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":134,"function":"sync","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/html/owncloud/apps/mail/lib/BackgroundJob/SyncJob.php","line":128,"function":"syncAccount","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/html/owncloud/lib/public/BackgroundJob/Job.php","line":47,"function":"run","class":"OCA\\Mail\\BackgroundJob\\SyncJob","type":"->"},{"file":"/var/www/html/owncloud/lib/public/BackgroundJob/TimedJob.php","line":85,"function":"start","class":"OCP\\BackgroundJob\\Job","type":"->"},{"file":"/var/www/html/owncloud/core/Service/CronService.php","line":176,"function":"start","class":"OCP\\BackgroundJob\\TimedJob","type":"->"},{"file":"/var/www/html/owncloud/core/Service/CronService.php","line":98,"function":"runCli","class":"OC\\Core\\Service\\CronService","type":"->"},{"file":"/var/www/html/owncloud/cron.php","line":52,"function":"run","class":"OC\\Core\\Service\\CronService","type":"->"}],"File":"/var/www/html/owncloud/apps/mail/lib/Service/MailManager.php","Line":816,"Previous":{"Exception":"Horde_Imap_Client_Exception_ServerResponse","Message":"IMAP error reported by server.","Code":0,"Trace":[{"file":"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php","line":4319,"function":"_getLine","class":"Horde_Imap_Client_Socket","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php","line":4243,"function":"_sendCmdChunk","class":"Horde_Imap_Client_Socket","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php","line":1753,"function":"_sendCmd","class":"Horde_Imap_Client_Socket","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Base.php","line":1731,"function":"_status","class":"Horde_Imap_Client_Socket","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/MailManager.php","line":814,"function":"status","class":"Horde_Imap_Client_Base","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":492,"function":"isPermflagsEnabled","class":"OCA\\Mail\\Service\\MailManager","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":269,"function":"runPartialSync","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->"},{"file":"/var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php","line":134,"function":"sync","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/html/owncloud/apps/mail/lib/BackgroundJob/SyncJob.php","line":128,"function":"syncAccount","class":"OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/html/owncloud/lib/public/BackgroundJob/Job.php","line":47,"function":"run","class":"OCA\\Mail\\BackgroundJob\\SyncJob","type":"->"},{"file":"/var/www/html/owncloud/lib/public/BackgroundJob/TimedJob.php","line":85,"function":"start","class":"OCP\\BackgroundJob\\Job","type":"->"},{"file":"/var/www/html/owncloud/core/Service/CronService.php","line":176,"function":"start","class":"OCP\\BackgroundJob\\TimedJob","type":"->"},{"file":"/var/www/html/owncloud/core/Service/CronService.php","line":98,"function":"runCli","class":"OC\\Core\\Service\\CronService","type":"->"},{"file":"/var/www/html/owncloud/cron.php","line":52,"function":"run","class":"OC\\Core\\Service\\CronService","type":"->"}],"File":"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php","Line":4622},"message":"Cron mail sync failed for account {accountId}","exception":"{\"class\":\"OCA\\Mail\\Exception\\ServiceException\",\"message\":\"Could not get message flag options from IMAP: IMAP error reported by server.\",\"code\":0,\"file\":\"/var/www/html/owncloud/apps/mail/lib/Service/MailManager.php:816\",\"trace\":\"#0 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(492): OCA\\Mail\\Service\\MailManager->isPermflagsEnabled()\\n#1 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(269): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->runPartialSync()\\n#2 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(134): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->sync()\\n#3 /var/www/html/owncloud/apps/mail/lib/BackgroundJob/SyncJob.php(128): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->syncAccount()\\n#4 /var/www/html/owncloud/lib/public/BackgroundJob/Job.php(47): OCA\\Mail\\BackgroundJob\\SyncJob->run()\\n#5 /var/www/html/owncloud/lib/public/BackgroundJob/TimedJob.php(85): OCP\\BackgroundJob\\Job->start()\\n#6 /var/www/html/owncloud/core/Service/CronService.php(176): OCP\\BackgroundJob\\TimedJob->start()\\n#7 /var/www/html/owncloud/core/Service/CronService.php(98): OC\\Core\\Service\\CronService->runCli()\\n#8 /var/www/html/owncloud/cron.php(52): OC\\Core\\Service\\CronService->run()\\n#9 {main}\",\"previous\":{\"class\":\"Horde_Imap_Client_Exception_ServerResponse\",\"message\":\"IMAP error reported by server.\",\"code\":0,\"file\":\"/var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php:4622\",\"trace\":\"#0 /var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php(4319): Horde_Imap_Client_Socket->_getLine()\\n#1 /var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php(4243): Horde_Imap_Client_Socket->_sendCmdChunk()\\n#2 /var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php(1753): Horde_Imap_Client_Socket->_sendCmd()\\n#3 /var/www/html/owncloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Base.php(1731): Horde_Imap_Client_Socket->_status()\\n#4 /var/www/html/owncloud/apps/mail/lib/Service/MailManager.php(814): Horde_Imap_Client_Base->status()\\n#5 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(492): OCA\\Mail\\Service\\MailManager->isPermflagsEnabled()\\n#6 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(269): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->runPartialSync()\\n#7 /var/www/html/owncloud/apps/mail/lib/Service/Sync/ImapToDbSynchronizer.php(134): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->sync()\\n#8 /var/www/html/owncloud/apps/mail/lib/BackgroundJob/SyncJob.php(128): OCA\\Mail\\Service\\Sync\\ImapToDbSynchronizer->syncAccount()\\n#9 /var/www/html/owncloud/lib/public/BackgroundJob/Job.php(47): OCA\\Mail\\BackgroundJob\\SyncJob->run()\\n#10 /var/www/html/owncloud/lib/public/BackgroundJob/TimedJob.php(85): OCP\\BackgroundJob\\Job->start()\\n#11 /var/www/html/owncloud/core/Service/CronService.php(176): OCP\\BackgroundJob\\TimedJob->start()\\n#12 /var/www/html/owncloud/core/Service/CronService.php(98): OC\\Core\\Service\\CronService->runCli()\\n#13 /var/www/html/owncloud/cron.php(52): OC\\Core\\Service\\CronService->run()\\n#14 {main}\"}}","CustomMessage":"Cron mail sync failed for account 20"},"id":"69a870efcc9ee"}

[rayyume]

same issue here with iCloud Mail

[chetty-the-yeti]

Also experiencing this bug with iCloud Mail on Nextcloud 33.0.2 and Mail app 5.7.1. The error is spamming the logs every few seconds making the log unmanageable. Worked around the log growth by setting log_rotate_size but the Mail app is effectively non-functional for iCloud accounts. Happy to wait for a patch but wanted to add another affected user to this report.

Undefined array key "id" at /config/www/nextcloud/apps/mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php#1007

[kesselb]

@rayyume @chetty-the-yeti has commenting the related line in #12506 (comment) the same effect for you?

[chetty-the-yeti]

Hi, @kesselb - thanks for your quick reply. I tried the workaround you suggested and it helped resolve the log spam.

Environment:

• Nextcloud 33.0.2.2
• Mail app 5.7.7
• IMAP accounts: iCloud (imap.mail.me.com:993) and cPanel hosted accounts
• Running in Docker (linuxserver/nextcloud image)

IMAP debug log for iCloud account:

Enabled per-account debug logging as described in the [Nextcloud Mail troubleshooting docs](https://docs.nextcloud.com/server/latest/admin_manual/groupware/troubleshooting.html#logging-the-imap-smtp-sieve-connections):

>> Connection to: imap://imap.mail.me.com:993/
S: * OK [CAPABILITY XAPPLEPUSHSERVICE IMAP4 IMAP4rev1 SASL-IR AUTH=ATOKEN AUTH=PLAIN AUTH=ATOKEN2 AUTH=XOAUTH2]
C: 1 AUTHENTICATE PLAIN
S: 1 OK user authenticated
C: 2 CAPABILITY
S: * CAPABILITY XAPPLEPUSHSERVICE IMAP4 IMAP4rev1 CONDSTORE ENABLE QRESYNC QUOTA XAPPLELITERAL NAMESPACE UIDPLUS UNSELECT SORT ESEARCH ESORT CONTEXT=SORT WITHIN SASL-IR ID IDLE X-APPLE-REMOTE-LINKS LIST-STATUS
S: 2 OK Completed

iCloud does advertise the ID capability, which matches what you saw on your end. The iCloud version string from the server banner was 2606B27, slightly different from the 2606B152 you reported.

Workaround applied:

Commented out lines 45-53 in [mail/lib/IMAP/HordeImapClient.php](https://github.com/nextcloud/mail/blob/d4b222ad37d39e08f92c19590792196049ec3725/lib/IMAP/HordeImapClient.php#L45-L53) to disable the ID sending block:

public function login() {
    parent::login();

//    if ($this->capability->query('ID')) {
//        try {
//            $this->sendID();
//            /* ID is queued - force sending the queued command. */
//            $this->_sendCmd($this->_pipeline());
//        } catch (Horde_Imap_Client_Exception_NoSupportExtension) {
//            // Ignore if server doesn't support ID extension.
//        }
//    }
}

Also added a null coalescing operator to line 1007 in mail/vendor/bytestream/horde-imap-client/lib/Horde/Imap/Client/Socket.php:

// Before
$temp['id'] = $cmd->pipeline->data['id'];

// After
$temp['id'] = $cmd->pipeline->data['id'] ?? [];

After clearing the log and running a manual sync, no new errors appeared. Mailbox is still accessible and syncing correctly across all accounts. Hope this helps narrow down the fix.

[kesselb]

What happens when you uncomment the sendID block in login and just keep the null coalescing in 1007?